Usage Patterns for Apache HBase

From Shared-All to Shared-Nothing 

Successfully used Patterns in 

application and table design 

with Hbase 

Bob Schulze, eCircle AG 

March 2010 @ Berlin Apache Hadoop Get Together 

-Patterns

➲ You have Big Data 

Audience 

➲ Your Organization needs predictable scaling 

options 

➲ You need to be flexible with your Data 

➲ You are a Techie Person 


➲ What is shared? 

Content 

➲ Recap RDBMS vs HBase/BigTable 

➲ Example: Credid-Card Processing 

➲ Storage Patterns 

➲ Application Design Proposal 

➲ Missing: Call for Features 

➲ HbaseExplorer 


Shared ..somewhat 

➲ Representation and 

Business Layers have 

well known scaling 

patterns 

➲ Many of these patterns 

rely on a transactional 

database underneath 

➲ Distributed transactions 

are expensive 


Shared ..somewhat 

➲ Representation and 

Business Layers have 

well known scaling 

patterns 

➲ Many of these patterns 

rely on a transactional 

database underneath 

➲ Distributed transactions 

are expensive 


Shared ..almost nothing 

➲ All Business Threads 

can run independently a 

long way 

➲ Contention only within 

one Shard → More 

Shards, Less Contention 

➲ Highly Available and 

Consistent 

➲ Give away 

perfection:Transactions 

must be hand-made 


Shared ..almost nothing 

➲ All Business Threads 

can run independently a 

long way 

➲ Contention only within 

one Shard → More 

Shards, Less Contention 

➲ Highly Available and 

Consistent 

➲ Give away 

perfection:Transactions 

must be hand-made 



Content 








RDBMs Solutions 

Card Dealer Amount Location Currency 

Customer Card Name Address Email 

Card Model Valid From 

Customer Date Supporter Req-ID Status 

➲ Transactions 

➲ Access Rules 

➲ Types 

➲ FK's 

➲ Fixed 

structure 

➲ History? 

➲ Rows? 


Alternative: HBase 

➲ Key/Value with structure in the „fat“ values 

● Arbitrary keys, but retain sortability 

➲ Data stored in Shards (regionserver) by 

splitting up the key range 

➲ Values are organized in Families 

➲ All Data has history 


Card Number 

1233.45.33-23 

Card Number 

1233.45.33-24 

Hbase: Key-Value 


Hbase: Regionserver hold Shards 

a...k l...m n...z 


Recap: Hbase/BigTable Data Model 

➲ family+Column=Column Qualifier 


➲ Stored in own Files 

● Important for retrieval 

➲ Have own Settings 

● Compression 

● Versions 

● Timed Deletions (TTL) 

● Size Constraints 

● Counters 

Column Families 



Content 








Example: Credit Card Processing 

Card Dealer Amount Location Currency 

Customer Card Name Address Email 

Card Model Valid From 

Customer Date Supporter Req-Id Status 

Transaction 

Card Owner 

Card Properties 

Support Req's 


RowKey: Card Number 

Hbase main table Layout 

TS Card Transaction Owner Support Notes 

t5 registerCode= 

model= 

pinHash= 

ValidFrom= 

ValidTo= 

t4 = 

 

Location= 

A new card was 

issued to the 

customer 

pinAttempts= A Transaction was 

made 

t3 Reason= 

= 

 

Supporter= 

t2 City= 

Addressid= 

src=byTel 

operator= 

t1 Email= 

 

src=web 

Reason= 

= 

Solved 

Supporter= 

Support Request from 

Customer 

Address-Change by 

support 

Email-Change from 

WebSite 


Supplementary (index-) Tables 

➲ Email to Card Mapping 

RowKey: md5(email) 

Card 

 

 

Allows to do lookups by a given email 

Index can be maintained without transaction! 

➲ Address references 

RowKey: addressid Address 

Sample for a simple relation 

Can be further encrypted 

Name= 

City= 

Street= 



Content 








Patterns to Store Data, why? 

➲ We can talk about it 

➲ Based on Space efficiency 

● Even if space is cheap, data has to be searched through and has 

to be moved 

➲ Based on Lookup efficiency 

● Most Data is stored sorted 

➲ Used for direct lookups as well as in MR 

aggregations 


Pattern: swim-above 

➲ Most recent value at top (in API) 

● Where was the last Transaction? 

get(Cardid: 123.22.34-24, Family: Transaction, Column: Location) 


t5 registerCode=123 

model=superFlash 

pinHash=aw3224hhds 

ValidFrom=se344qq1 

ValidTo=12esdrf43q.q 

t4 D123376=123E 

Location=Berlin 

t3 D2231=82.22E 

Location=Munich 

● What is the current model? 


issued to the 

customer 

pinAttempts=1 A Transaction was 

made 


made 

get(Cardid: 123.22.34-24, Family: Card, Column: model) 


Pattern: swim-above 

➲ Most recent value at top (in API) 

● Where was the last Transaction? 

get(Cardid: 123.22.34-24, Family: Transaction, Column: Location) 


t5 registerCode=123 

model=superFlash 

pinHash=aw3224hhds 

ValidFrom=se344qq1 

ValidTo=12esdrf43q.q 

t4 D123376=123E 

Location=Berlin 

t3 D2231=82.22E 

Location=Munich 

● What is the current model? 


issued to the 

customer 


made 


made 

get(Cardid: 123.22.34-24, Family: Card, Column: model) 


Pattern: Data grouped by Timestamp 

● Who changed the Address to „Munich“ ? 

1. Figure out the Timestamp(s) 

get(Cardid: 123.22.34.24, City=Munich) → ts2 

2. get the fields for this TS 

get(Cardid: 123.22.34-24, timestamp: t2) 


t3 Reason= 

= 

 

Supporter= 

t2 City=Munich 

Addressid= 

src=byTel 

operator= 

t1 Email= 

 

src=web 

Reason=Call-In 

R213=Solved 

Supporter=PaulG 

Support Request 

from Customer 

Address-Change 

by support 

Email-Change 

from WebSite 


Pattern: Data grouped by Timestamp 

● Who changed the Address to „Munich“ ? 

1. Figure out the Timestamp(s) 

get(Cardid: 123.22.34.24, City=Munich) → ts2 

2. get the fields for this TS 

get(Cardid: 123.22.34-24, timestamp: t2) 


t3 Reason= 

= 

 

Supporter= 


Addressid= 

src=byTel 

operator= 

t1 Email= 

 

src=web 


R213=Solved 



from Customer 


by support 

Email-Change 

from WebSite 


Pattern: ColumnName-Is-Value 

➲ No value, Often useful for indexes 

RowKey: 123.23452-24 


Card 

123.23662-21 

123.23452-24 


t3 Reason= 

= 

 

Supporter= 


Addressid= 

src=byTel 

operator= 


R213=Solved 



from Customer 


support 


Pattern: ColumnName-Is-Value 

➲ No value, Often useful for indexes 

RowKey: 123.23452-24 



t3 Reason= 

= 

 

Supporter= 


Addressid= 

src=byTel 

operator= 

Card 

123.23662-21 

123.23452-24 


R213=Solved 


● Where did al.lias@gmx.com use his cards? 

index.get(9fc81d4292e6a404c2d64c9eaa66e43a) → Cardids 

cards.get(123.23452-24,...) 


from Customer 


support 


Pattern: Column-Enum 

● What is the status of Support-Request R213 

(status is one of: Opened, Reviewed, Assigned, Pending, Solved) 

get(Cardid: 123.22.34.24, Family: Support, Column: R213) 


t3 Reason= 

= 

 

Supporter= 


Addressid= 

src=byTel 

operator= 

t1 Email= 

 

src=web 


R213=Solved 



from Customer 


by support 

Email-Change 

from WebSite 


Pattern: Atomic Counters 

● Solves the common Problem when many clients try to update one/few 

rows in a RDBMS table 

● Use a separate table/family/column, use the key or family to partition the 

load 

● Example: Write a Record and add up some stats 

1. cards.insert(key: 123.22.34.24, Column: R213, Value=Solved,...) 

2. stats.increment(key: 123.22.34.24, Column: SREGSPERMONTH,+1) 

● Small overhead even on excessive use: 

:year-month-date= 

:year-month= 

● timestamps! 


➲ Constant Costs 

Pattern: index table 

● Always one more insert to (another sharded) index table 

➲ Lock Free 

● Versions=1 

➲ Only „eventually“ consistant 

● But on our control! 


➲ Swim-above 

Pattern Summary 

➲ Data grouped by timestamp 

➲ ColumnName-is-Value 

➲ Column-Enum 

➲ Atomic Counter 

➲ Index table 



Content 








Application Design 

➲ Persistance Code 

moves out of App 

● Gets reusable! 

● Easy to test 

➲ Fix what's 

missing 

● Security / Access Control 

● Firewall 

● Index Handling 

● Transactions 

● ORM mappings 



Content 








Hbase: missing pieces 

➲ Multi-Get/Scan would 

allow to read data 

from multiple Region 

Servers in parallel to 

one client 

➲ Same with Multi-Put 

➲ Patches avail., 0.21 



➲ Server Side Processing reduces data 

transfer and distributes computing 

● Scan transfers only matches 

scan rowkey=, dealer= 

● Allows aggregations on server side (1 st map already on region 

server) 

● Some server-side Scan-Filters help already today 

● Java Expression Language? 



➲ Bloomfilter 

● Reduce key-lookup time 

● Disappeared in 0.20.x, planned to be reanimated in 0.21 

➲ Hfile persistant internal value index 

● Value indexes / Value compression 

● Timestamp Index 



Content 








Hbaseexplorer: scan 


Hbaseexplorer: cluster setup 


Hbaseexplorer; Table Definition 


Hbaseexplorer: statistics 


hbaseexplorer 

➲ Complements Ruby-Shell 

● Visual Data Representations 

● UI Tools for Table Creation 

● Embedded M/R Jobs for Table Copy or Statistics 

collection 

➲ Open Source @ SourceForge 

● Java, WebApp, Grails 

● Coders needed! 

➲ More info 

● http://althelies.wordpress.com/hbaseexplorer/ 


eCircle AG 

➲ Biggest Direct Email-Marketing Company in 

Europe 

➲ 10 yrs, 200 Employees, now in 6 Countries 

➲ Lots of data 

● 100Mio permission Emails / Day 

● Individualized Emails stored, trackings, hosting 

● Privacy challanges → even more data 

● We went through the classic RDBMS scaling story 

➲ We hire! 

● Java, UI (JSP, Ajax) 


Thank you! 

b.schulze@ecircle.com 

al.lias@gmx.de

Usage Patterns for Apache HBase

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